Herbicides and Lymphoma in Dogs

Last Modified: December 4, 2003

Question:

Dear OncoLink "Ask The Experts,"My dog developed lymphosarcoma. I saw articles linking the 2,4-d herbicide chemical to lymphoma in dogs. I realized I used a fertilizer weed control mix that contained this chemical. I only used it once, but she loved to eat the crab grass at the edges. I feel this may have triggered the cancer. Do you think this caused her cancer?

Answer:

Well, this is a very difficult question and hard to answer. However, the short answer is "NO", the herbicide did not cause the lymphoma. What causes lymphoma is not known. What is known is that there are risk factors for lymphoma, and if they are present an animal is more likely to develop lymphoma. 2,4-d herbicide is suggested to be a weak risk factor in a few studies of canine lymphoma. However, the fact is that this is an extremely common lawn chemical, and the vast majority of dogs exposed to this chemical do not develop lymphoma. At the most, it might have been a minor contributing factor along with a host of other predisposing factors. For example, several breeds of dogs are much more likely to develop lymphoma than the general population.